Writing instrument



FIG. 1 is a front perspective view of a writing instrument according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof;

FIG. 4 is a right side plan view thereof;

FIG. 5 is an enlarged top plan view thereof; and,

FIG. 6 is an enlarged bottom plan view thereof.

The broken line showing of the tip of the writing instrument is included for the purpose of ease of illustration and forms no part of the claimed design. 

The ornamental design for a writing instrument, as shown and described. 